Was just rereading - it was the radioactivity and the large natural satellite that was unique in his universe. Tides are interesting because once you have life in the oceans, it's a kind of forcing function to adapt to land conditions
Forcing function + making a stretch of land which is neither dry nor enterily wet. A gradient. If there are no tides the leap life has to make is much bigger.
"Nucleotide formation and polymerization are both more favored thermodynamically when subunit and nucleotide concentrations increase and the water concentration decreases (i.e., at low water activity)" [1].
Tide pools provide a regularly-cycling low-water and high-water environment. (And you get thermocycling, nutrient refreshment, and a path to the oceans, too.)
They're not a forcing function, generally, because we don't know how life formed. But I believe they're close to one in a RNA-first or metabolism-first origin-of-life universe.
